X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FSQLAHacks.pm;h=a1e6d1cbf1aa41888c00a523b6ae7e0207e91769;hb=4a80eede246c6cb2da4b15bcc00dbd6e56058c89;hp=7c8c725ed56a2240963542f56f917bc64ae15d98;hpb=83e09b5b5718416258f0db82f8547a7116b08301;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/SQLAHacks.pm b/lib/DBIx/Class/SQLAHacks.pm index 7c8c725..a1e6d1c 100644 --- a/lib/DBIx/Class/SQLAHacks.pm +++ b/lib/DBIx/Class/SQLAHacks.pm @@ -1,6 +1,10 @@ package # Hide from PAUSE DBIx::Class::SQLAHacks; +# This module is a subclass of SQL::Abstract::Limit and includes a number +# of DBIC-specific workarounds, not yet suitable for inclusion into the +# SQLA core + use base qw/SQL::Abstract::Limit/; use strict; use warnings; @@ -12,12 +16,13 @@ BEGIN { no warnings qw/redefine/; no strict qw/refs/; for my $f (qw/carp croak/) { + my $orig = \&{"SQL::Abstract::$f"}; *{"SQL::Abstract::$f"} = sub { local $Carp::CarpLevel = 1; # even though Carp::Clan ignores this, $orig will not - if (Carp::longmess() =~ /DBIx::Class::SQLAHacks::[\w]+\(\) called/) { + if (Carp::longmess() =~ /DBIx::Class::SQLAHacks::[\w]+ .+? called \s at/x) { __PACKAGE__->can($f)->(@_); } else { @@ -27,6 +32,9 @@ BEGIN { } } + +# Tries to determine limit dialect. +# sub new { my $self = shift->SUPER::new(@_); @@ -39,14 +47,12 @@ sub new { $self; } - # Some databases (sqlite) do not handle multiple parenthesis -# around in/between arguments. A tentative x IN ( ( 1, 2 ,3) ) +# around in/between arguments. A tentative x IN ( (1, 2 ,3) ) # is interpreted as x IN 1 or something similar. # # Since we currently do not have access to the SQLA AST, resort # to barbaric mutilation of any SQL supplied in literal form - sub _strip_outer_paren { my ($self, $arg) = @_; @@ -116,37 +122,190 @@ SQL sub _Top { my ( $self, $sql, $order, $rows, $offset ) = @_; + # mangle the input sql so it can be properly aliased in the outer queries + $sql =~ s/^ \s* SELECT \s+ (.+?) \s+ (?=FROM)//ix + or croak "Unrecognizable SELECT: $sql"; + my $sql_select = $1; + my @sql_select = split (/\s*,\s*/, $sql_select); + + # we can't support subqueries (in fact MSSQL can't) - croak + if (@sql_select != @{$self->{_dbic_rs_attrs}{select}}) { + croak (sprintf ( + 'SQL SELECT did not parse cleanly - retrieved %d comma separated elements, while ' + . 'the resultset select attribure contains %d elements: %s', + scalar @sql_select, + scalar @{$self->{_dbic_rs_attrs}{select}}, + $sql_select, + )); + } + + my $name_sep = $self->name_sep || '.'; + my $esc_name_sep = "\Q$name_sep\E"; + my $col_re = qr/ ^ (?: (.+) $esc_name_sep )? ([^$esc_name_sep]+) $ /x; + + my $rs_alias = $self->{_dbic_rs_attrs}{alias}; + my $quoted_rs_alias = $self->_quote ($rs_alias); + + # construct the new select lists, rename(alias) some columns if necessary + my (@outer_select, @inner_select, %seen_names, %col_aliases, %outer_col_aliases); + + for (@{$self->{_dbic_rs_attrs}{select}}) { + next if ref $_; + my ($table, $orig_colname) = ( $_ =~ $col_re ); + next unless $table; + $seen_names{$orig_colname}++; + } + + for my $i (0 .. $#sql_select) { + + my $colsel_arg = $self->{_dbic_rs_attrs}{select}[$i]; + my $colsel_sql = $sql_select[$i]; + + # this may or may not work (in case of a scalarref or something) + my ($table, $orig_colname) = ( $colsel_arg =~ $col_re ); + + my $quoted_alias; + # do not attempt to understand non-scalar selects - alias numerically + if (ref $colsel_arg) { + $quoted_alias = $self->_quote ('column_' . (@inner_select + 1) ); + } + # column name seen more than once - alias it + elsif ($orig_colname && ($seen_names{$orig_colname} > 1) ) { + $quoted_alias = $self->_quote ("${table}__${orig_colname}"); + } + + # we did rename - make a record and adjust + if ($quoted_alias) { + # alias inner + push @inner_select, "$colsel_sql AS $quoted_alias"; + + # push alias to outer + push @outer_select, $quoted_alias; + + # Any aliasing accumulated here will be considered + # both for inner and outer adjustments of ORDER BY + $self->__record_alias ( + \%col_aliases, + $quoted_alias, + $colsel_arg, + $table ? $orig_colname : undef, + ); + } + + # otherwise just leave things intact inside, and use the abbreviated one outside + # (as we do not have table names anymore) + else { + push @inner_select, $colsel_sql; + + my $outer_quoted = $self->_quote ($orig_colname); # it was not a duplicate so should just work + push @outer_select, $outer_quoted; + $self->__record_alias ( + \%outer_col_aliases, + $outer_quoted, + $colsel_arg, + $table ? $orig_colname : undef, + ); + } + } + + my $outer_select = join (', ', @outer_select ); + my $inner_select = join (', ', @inner_select ); + + %outer_col_aliases = (%outer_col_aliases, %col_aliases); + + # deal with order croak '$order supplied to SQLAHacks limit emulators must be a hash' if (ref $order ne 'HASH'); $order = { %$order }; #copy - my $last = $rows + $offset; + my $req_order = $order->{order_by}; - my $req_order = $self->_order_by ($order->{order_by}); + # examine normalized version, collapses nesting + my $limit_order; + if (scalar $self->_order_by_chunks ($req_order)) { + $limit_order = $req_order; + } + else { + $limit_order = [ map + { join ('', $rs_alias, $name_sep, $_ ) } + ( $self->{_dbic_rs_attrs}{_source_handle}->resolve->primary_columns ) + ]; + } - my $limit_order = $req_order ? $order->{order_by} : $order->{_virtual_order_by}; + my ( $order_by_inner, $order_by_outer ) = $self->_order_directions($limit_order); + my $order_by_requested = $self->_order_by ($req_order); - delete $order->{$_} for qw/order_by _virtual_order_by/; + # generate the rest + delete $order->{order_by}; my $grpby_having = $self->_order_by ($order); - my ( $order_by_inner, $order_by_outer ) = $self->_order_directions($limit_order); + # short circuit for counts - the ordering complexity is needless + if ($self->{_dbic_rs_attrs}{-for_count_only}) { + return "SELECT TOP $rows $inner_select $sql $grpby_having $order_by_outer"; + } - $sql =~ s/^\s*(SELECT|select)//; + # we can't really adjust the order_by columns, as introspection is lacking + # resort to simple substitution + for my $col (keys %outer_col_aliases) { + for ($order_by_requested, $order_by_outer) { + $_ =~ s/\s+$col\s+/ $outer_col_aliases{$col} /g; + } + } + for my $col (keys %col_aliases) { + $order_by_inner =~ s/\s+$col\s+/ $col_aliases{$col} /g; + } - $sql = <<"SQL"; - SELECT * FROM - ( - SELECT TOP $rows * FROM + + my $inner_lim = $rows + $offset; + + $sql = "SELECT TOP $inner_lim $inner_select $sql $grpby_having $order_by_inner"; + + if ($offset) { + $sql = <<"SQL"; + + SELECT TOP $rows $outer_select FROM ( - SELECT TOP $last $sql $grpby_having $order_by_inner - ) AS foo + $sql + ) $quoted_rs_alias $order_by_outer - ) AS bar - $req_order +SQL + + } + if ($order_by_requested) { + $sql = <<"SQL"; + + SELECT $outer_select FROM + ( $sql ) $quoted_rs_alias + $order_by_requested SQL - return $sql; + + } + + $sql =~ s/\s*\n\s*/ /g; # parsing out multiline statements is harder than a single line + return $sql; +} + +# action at a distance to shorten Top code above +sub __record_alias { + my ($self, $register, $alias, $fqcol, $col) = @_; + + # record qualified name + $register->{$fqcol} = $alias; + $register->{$self->_quote($fqcol)} = $alias; + + return unless $col; + + # record unqualified name, undef (no adjustment) if a duplicate is found + if (exists $register->{$col}) { + $register->{$col} = undef; + } + else { + $register->{$col} = $alias; + } + + $register->{$self->_quote($col)} = $register->{$col}; } @@ -158,6 +317,12 @@ sub _find_syntax { return $self->{_cached_syntax} ||= $self->SUPER::_find_syntax($syntax); } +my $for_syntax = { + update => 'FOR UPDATE', + shared => 'FOR SHARE', +}; +# Quotes table names, handles "limit" dialects (e.g. where rownum between x and +# y), supports SELECT ... FOR UPDATE and SELECT ... FOR SHARE. sub select { my ($self, $table, $fields, $where, $order, @rest) = @_; @@ -177,18 +342,14 @@ sub select { my ($sql, @where_bind) = $self->SUPER::select( $table, $self->_recurse_fields($fields), $where, $order, @rest ); - $sql .= - $self->{for} ? - ( - $self->{for} eq 'update' ? ' FOR UPDATE' : - $self->{for} eq 'shared' ? ' FOR SHARE' : - '' - ) : - '' - ; + if (my $for = delete $self->{_dbic_rs_attrs}{for}) { + $sql .= " $for_syntax->{$for}" if $for_syntax->{$for}; + } + return wantarray ? ($sql, @{$self->{from_bind}}, @where_bind, @{$self->{having_bind}}, @{$self->{order_bind}} ) : $sql; } +# Quotes table names, and handles default inserts sub insert { my $self = shift; my $table = shift; @@ -204,6 +365,7 @@ sub insert { $self->SUPER::insert($table, @_); } +# Just quotes table names. sub update { my $self = shift; my $table = shift; @@ -211,6 +373,7 @@ sub update { $self->SUPER::update($table, @_); } +# Just quotes table names. sub delete { my $self = shift; my $table = shift; @@ -439,12 +602,15 @@ sub limit_dialect { return $self->{limit_dialect}; } +# Set to an array-ref to specify separate left and right quotes for table names. +# A single scalar is equivalen to [ $char, $char ] sub quote_char { my $self = shift; $self->{quote_char} = shift if @_; return $self->{quote_char}; } +# Character separating quoted table names. sub name_sep { my $self = shift; $self->{name_sep} = shift if @_; @@ -452,50 +618,3 @@ sub name_sep { } 1; - -__END__ - -=pod - -=head1 NAME - -DBIx::Class::SQLAHacks - This module is a subclass of SQL::Abstract::Limit -and includes a number of DBIC-specific workarounds, not yet suitable for -inclusion into SQLA proper. - -=head1 METHODS - -=head2 new - -Tries to determine limit dialect. - -=head2 select - -Quotes table names, handles "limit" dialects (e.g. where rownum between x and -y), supports SELECT ... FOR UPDATE and SELECT ... FOR SHARE. - -=head2 insert update delete - -Just quotes table names. - -=head2 limit_dialect - -Specifies the dialect of used for implementing an SQL "limit" clause for -restricting the number of query results returned. Valid values are: RowNum. - -See L for details. - -=head2 name_sep - -Character separating quoted table names. - -See L for details. - -=head2 quote_char - -Set to an array-ref to specify separate left and right quotes for table names. - -See L for details. - -=cut -